1. Technical Field
The present invention relates to light source modules and, particularly, to a light source module with a high heat-dissipation efficiency.
2. Description of Related Art
A light emitting diode (LED) is one type of semiconductor light source, and the electrical and optical characteristics and life span thereof are greatly temperature-dependent. Generally, a high working temperature will cause a deterioration of an internal quantum efficiency of the LED and shorten the life span thereof. Furthermore, a resistance of a semiconductor has a negative temperature coefficient and tends to be reduced with an increase in the working temperature. Such a reduced resistance will correspondingly result in a larger current at a given voltage and the generation of excessive heat. If the excessive heat cannot be effectively dissipated, a phenomenon of heat accumulation will be difficult to avoid, and, accordingly, the deterioration of the LED can be expected to be accelerated.
Referring to FIG. 3, a typical light source module 200 includes a printed circuit board 220, a heat-dissipating member 240, and a number of LEDs 260. The printed circuit board 220 defines two opposite surfaces (not labeled). The heat-dissipating member 240 and the LEDs 260 are respectively mounted on the two opposite surfaces of the printed circuit board 220. The heat-dissipating member 240 is thermally connected with the printed circuit board 220, with a thermal grease or paste interposed therebetween to promote heat conduction. The heat-dissipating member 240 usually defines a number of heat dissipation fins 242 on a surface thereof directed away from the printed circuit board 220. Such heat dissipation fins 242 are configured (i.e., structured and arranged) for facilitating the dissipation of heat from the light source module 200. The LEDs 260 are electrically connected with the printed circuit board 220.
However, the LEDs 260 are spaced from the heat-dissipating member 240 via the printed circuit board 220, which generally has a relatively low thermal conductivity (i.e., effectively acts more like a thermal insulator). Due to such spacing and the presence of the printed circuit board 220, heat generated from the LEDs 260 during operation would not be directly transmitted to the heat-dissipating member 240, thus not permitting effective heat dissipation. As such, the above-described phenomenon of heat accumulation will likely appear, and the deterioration of the light source module 200 would be accelerated as a result, even though the heat-dissipating member 240 is provided.
Therefore, what is needed is to provide a light source module with high heat-dissipation efficiency.